Paradoxical, but true: Great improvisation requires extensive practice and expertise. My own studies of jazz and improv theater groups shows this to be true, as I describe in my 2007 book Group Genius: The Creative Power of Collaboration. Most people find this to be surprising, because our mythical image of the great improviser is someone who is driven by internal impulse, genius-level performance creativity. Stereotypes like saxophonist Charlie Parker, high on heroin, blowing his horn at 2am in some New York jazz club.
It’s the same with every performance genre. This recent article in the New York Times tells the story of how spontaneity in a classical music performance emerged only after eleven days of 14-hour rehearsals. Of course, you can go too far: every theater professional is familiar with “overrehearsal” that drains the spontaneous spirit from a performance. But without rehearsal, familiarity, and expertise, you’ll never get effective spontaneity.
This reminds me of a famous quotation from comedian George Burns:
The most important thing in an actor is sincerity. If he can fake that, he’s got it made.